The subject invention relates generally to the use of cultured plant cell gums in food, pharmaceutical, cosmetic and other industrial applications, including their use in oil and gas well drilling and production and lithography, and in the manufacture of textiles, ink, adhesive, paper, paint, ceramics, agricultural chemical and cleaning or detergent agent
A variety of natural and semisynthetic complex carbohydrates or polysaccharides have been commercially important in human and pet food manufacturing; in the cosmetic, paper, textile, paint, agricultural, explosives, hydrolube, adhesive, ceramic, cleaning polish, detergent, fire fighting, ink, photography, lithography, and deodorant gel industries; and in mining, and gas well drilling and production. Natural complex carbohydrates and polysaccharides include seaweed extracts, plant exudates, seed or root extracts, and microbial polysaccharides produced by fermentation. Semisynthetic complex carbohydrates and polysaccharides include cellulose derivatives, low-methoxyl pectin, propylene glycol alginate, triethanolamine alginate and guar gum derivatives. Sandford, P. and Baird, J. (1983) xe2x80x9cIndustrial Utilization of Polysaccharidesxe2x80x9d in The Polysaccharides, Vol. 2, pp. 411-491.
The production of natural complex carbohydrates or polysaccharides is frequently problematic. For plant exudates and seed or root extracts, production is dependent on climate and harvest conditions. For example, gum arabic is an exudate from Acacia senegal trees. Gum production is stimulated by stripping the bark from the trees; the gum is collected by hand in the form of xe2x80x9cdried tears.xe2x80x9d Production of gum arabic can vary each year as a function of weather conditions, labor strikes, natural disasters, etc. Meer et al. (1975) Food Technology 29:22-30. The unreliable supply results in variable gum arabic cost. Seed gums, such as guar gums are expensive due to harvesting costs. Guar gum is derived from the seed of the guar plant Cyamopsis tetragonolobus. Processing involves removal of the seed coat, separation of the germ from the endosperm, and milling of the endosperm. Sandford, P. and Baird, J. (1983), supra. Further, gums obtained from such sources may have variable quality and exhibit variable functional properties.
The production of seaweed extracts can also be problematic. Agar production is labor intensive in that it involves the harvesting of red seaweed by hand: in some areas of the world, divers in full pressure suits collect individual plants in deep water; in other places, the seaweed can be collected at low tide without the use of diving equipment. Carrageenan or Irish Moss is produced from another red seaweed harvested by raking and hand gathering. Algin is produced from brown algae which can be harvested manually or with small mechanical harvesters. Sandford, P. and Baird, J. (1983), supra.
Further, hand harvesting can introduce a purity problem. For example, hand collected lots of gum arabic are seldom pure; samples are classified according to grade which depends on color, and contamination with foreign bodies such as wood or bark (VanNostrand""s Scientific Encyclopedia, 7th ed. (1989) D. Considine (ed.), Vol. I, p. 1389).
Microbial fermentation gums such as xanthan gum avoid many of the difficulties associated with harvesting of plant exudates or extraction of algae because production is carried out in fermentation facilities. However, xanthan gum production poses other problems. Xanthan gum is produced by Xanthamonas campestris, which presents a cell disposal problem because X. campestris is a plant pathogen (Scaad, N. W. (1982) Plant Disease 66(10):882-890). Xanthan gum has also been objected to as being too expensive for certain applications such as drilling mud. See, e.g., Kirk-Othmer Chemical Engineering Encyclopedia (3rd. ed. 1981) 17:153.
Thus, there is a clear need in a number of industries for a reliable, relatively inexpensive gum or class of gums that do not create a disposal problem. While a number of plant cells have been observed to produce polysaccharide and/or complex carbohydrates when cultured (Aspinall, G. and Molloy, J. (1969) Canadian J. Biochem. 47:1063-1070; Fincher, G. et al. (1983) Ann. Rev. Plant Physiol. 34:47-70; Clarke, A. et al. (1979) 18:521-540; McNeil, M. et al. (1984) Ann. Rev. Biochem. 53:625-663; Hale, A. et al. (1987) Plant Cell Reports 6:435-438; and Bacic, A. et al. (1987) Australian J. Plant Physiol. 14:633-641), it has not been suggested that such cultured plant cell gums might be suitable in the pharmaceutical, paper, textile, paint, agricultural, explosives, hydrolube, adhesive, ceramic, cleaning polish, detergent, fire fighting, ink, photography and lithography industries; or in mining, and oil and gas well drilling and production. Only Otsuji, K. et al. EP 0 285 829 (published Oct. 12, 1988) have utilized cultured Polianthus gum in cosmetic applications.
Related work by the inventors hereof has been published in WO 8806627 (1988) and WO 9402113 (1994). WO 8806627 relates in general to the use of cultured plant cell gums in the manufacture of food products as emulsifiers, thickening agents, gelling agents and the like. Cultured plant cell gums of Pyrus, Prunus, and Rosa are specifically exemplified. U.S. Pat. No. 5,133,979 (issued Jul. 28, 1992) and U.S. Pat. No. 5,296,245 (issued Mar. 22, 1994) are directed to similar subject matter. WO 9402113 relates to the general use of cultured plant cell gums as emulsifiers, viscosifiers, and the like for the manufacture of industrial, pharmaceutical or cosmetic products. Cultured plant cell gums from suspension cultures of Nicotiana, Pyrus, Phleum and Lolium are exemplified
The subject invention comprises the use of cultured plant cell gums produced from gum-secreting cells of vascular plants in a variety of food, pharmaceutical, veterinary, cosmetic and industrial applications including, without limitation, textiles, paper, adhesives, inks, lithography, ceramics, cleaning detergents, firefighting, agricultural, explosives and oil and gas wells. The cultured plant cell gums are useful in general as viscosifiers, as thickening, gelling, emulsifying, dispersing, suspending, stabilizing, encapsulating, flocculating, film-forming, sizing, adhesive, texture-modifying, enrobing, binding and/or coating agents, and/or as lubricants, water retention agents and coagulants. Any cultured plant cell gum can be useful in the subject industrial, pharmaceutical and cosmetic applications described herein. This invention is more specifically directed to particular plant cell gums which have particularly useful rheological properties and the use of such gums in food, pharmaceutical, veterinary, cosmetic and other industrial applications. The invention also relates to several specific applications for which cultured plant cell gums are particularly suitable.
In one embodiment the invention relates to cultured plant cell gum secreted in culture of plants of the family Aizoaceae. This family of succulents includes plants of the genera: Mesembryanthemum, Aptenia, Carpobrotus, Delosperma, Hereroa and Rushia, among others. Of more interest are plant cell gums of the Mesembryanthemum, Aptenia, or Carpobrotus. The plant cell gums of this family are particularly useful as emulsification agents and emulsion stabilizing agents. The plant cell gums of these plants are very active emulsifiers. Plant cell gums of species of Mesembryanthemum are particularly useful in the formation of low viscosity, low-droplet-size emulsions, e.g., cloud emulsions. Low-droplet-size emulsions find extensive use, for example in the food industry, for manufacture of soft drinks. Methods of use of these cultured plant cell gums are provided.
In another embodiment the invention relates to cultured plant cell gum secreted in culture of monocot plants, including plants of the family Poaceae including plants of the genera Phleum and Panicum, among others. Cultured plant cell gums of Phleum (particularly those of timothy grass, P. pratense) exhibit good gelling ability and high viscosity. Phleum cultured plant cell gum can serve as a substitute for guar gum or hydroxymethylcellulose. Panicum gums exhibit high viscosity and visco-elastic properties and have a variety of applications in the food and other industries, particularly for the preparation of drilling muds. Panicum cultured plant cell gums are useful in the manufacture of chemical sprays, particularly for agricultural sprays to inhibit satellite droplet formation in such sprays. Methods of use of these cultured plant cell gums are provided.
Table 1A provides a preferred list of families, genera and species of plants that are useful in for the production of cultured plant cell gums. Table 1B provides a list of more preferred families, genera and species of plants useful for production of cultured plant cell gums. Plant families of more interest for production of cultured plant cell gums include: Actinidaceae, Agavaceae, Aizoaceae, Asteraceae, Cucurbitaceae, Fabaceae, Malvaceae, Mimosaceae, Poaceae, Rosaceae, and Solanaceae. Plant genera of more interest for production of cultured plant cell gums include: Acacia, Actinidia, Carpobrotus, Chichorium, Cucumis, Glycine, Hibiscus, Hordeum, Letuca, Lycopersicon, Malus, Medicago, Mesembryanthemum, Nicotiana, Oryza, Panicum, Phalaris, Phleum, Polianthus, Pyrus, Rosa, Sida, Solanum, Trifolium, Trigonella, and Zea. Plant species of more interest for production of cultured plant cell gums include: Acacia senegal, Actinidia deliciosa, Carpobrotus spp., Chichorium intybus, Cucumis sativus, Glycine max, domesticus, Medicago sativa, Mesembryanthemum spp., Oryza sativa, Panicum miliaceun, Hibiscus esculentus, Hordeum vulgare, Letuca sativa, Lycopersicon esculentum, Malus domesticus, Phalaris aquaticus, Phleum pratense, Polianthus tuberosa, Rosa glauca, Sida rhombifolia, Solanum, Trifolium repens, Trifolium pratense, Trigonellafoenum-graceum, and Zea mays. Cultured plant cell gums produced by gum-secreting cells of plants of the foregoing families, genera and species are useful as emulsifying agents, viscosifying agents, gelling agents, thickening agents, dispersing or suspending agents, emulsion stabilizing agents, encapsulating agents, flocculating agents, film-forming agents, sizing agents, binding and/or coating agents, and/or as lubricants, water retention agents and coagulants or in adhesive compositions and the like in food, pharmaceutical, veterinary, cosmetic and other industrial applications. Methods of use of these cultured plant cell gums are provided.
In general, plant cell lines that produce at least about 0.05% (w/v) gum in the final fermentor culture broth, are preferred to reduce production costs. Plant cell lines that produce at least about 0.5%, 2.0%, and 10.0% (w/v) gum in the final culture broth are increasingly preferred. In one embodiment, the cultured plant cell gums employed in such applications are cultured plant cell gums having arabinogalactan proteins (AGPs) of at least about 4.0% (w/w). As discussed herein, choice of explant and culture conditions for the plant cells can affect functional properties of the gum product.
Cultured plant cell gum products can be used as a substitute for prior art gums, such as gum arabic and guar gum. The cultured plant cell gums can also be used as a substitute for xanthan gum, alginic acid, agar, calcium alginate, carrageenan, guar gum, karaya gum, locust bean gum, potassium or sodium alginate, tragacanth gum and others. For example, the cultured plant cell gums can be used as thickening agents and/or emulsifying agents to replace gum arabic in adhesives, inks, textile printing and cosmetics. The cultured plant cell gums can be used to replace alginic acid as an emulsifier, thickening agent, suspending agent, waterproofing agent, etc. in toothpaste, cosmetics, pharmaceuticals, textile sizing, coatings, oil-well drilling muds, and concrete. The cultured plant cell gums can be used to replace agar as a gelling agent, protective colloid, in photographic emulsions or other applications. The cultured plant cell gums can be used to replace calcium alginate as a thickening agent, stabilizer, etc. in synthetic fibers. Carrageenan, which can be used as an emulsifier, protective colloid, stabilizing agent, etc. in toothpastes, cosmetics and pharmaceuticals, can be replaced by cultured plant cell gums. Cultured plant cell gums can substitute for guar gum, which functions as a thickening agent, emulsifier, etc. in paper, cosmetics, pharmaceuticals, textiles, printing, polishing, and as a fracture aid in oil wells. Cultured plant cell gums can also replace karaya gum as a protective colloid, stabilizer, thickener, emulsifier, etc. in pharmaceuticals, textile coatings and adhesives. Cultured plant cell gums can replace locust bean gum (carob-bean gum) as a stabilizer, thickener, emulsifier, etc. in packaging material, cosmetics, sizing and finishes for textiles, pharmaceuticals and paints. Potassium or sodium alginate, which can function as an emulsifier, thickening agent, stabilizer, etc. in pharmaceuticals, textile printing, cement compositions, paper coatings, and in some water-base paints, can be replaced by cultured plant cell gums. Cultured plant cell gums can replace tragacanth gum as an emulsifying agent, coating agent, thickening agent, stabilizer, etc. in pharmaceuticals, adhesives, leather dressings, textile printing and sizing, dyes, toothpastes, hairwave preparations, soap chips and powders. Xanthan gum, which is used as a thickening, suspending, emulsifying agent, stabilizing agent, etc. in oil and gas well drilling muds and other applications, can also be replaced by cultured plant cell gums. In replacing such prior art gums, the cultured plant cell gums can offer unexpectedly improved results. Often, cultured plant cell gums can surprisingly be used in smaller quantities than the prior art gums to achieve equivalent functional results. Further, production of the cultured plant cell gums do not present the cell disposal problem that xanthan gum production does.
The cultured plant cell gums are not useful in applications where their utilities or properties are significantly compromised or destroyed. Organic solvents such as alcohol, acetone and ether and the like can disrupt function by causing precipitation of the cultured plant cell gums. To maintain the gums"" emulsification, thickening or gelling properties, it is preferred that the temperature of the gum-containing solution or mixture be maintained between about 4xc2x0 and 90xc2x0 C. and have a pH of neutral to slightly alkaline. As the pH increases, the thickening capacity of the gums decreases. However, even at elevated pH, viscosity can increase with increased ionic strength. Gum-containing solutions can gel in the presence of divalent cations such as calcium, and as temperature decreases, gel strength increases. Typically, stable gels are produced in the pH range of between about 3 to 10 and in the presence of calcium ions. Further, heating and cooling of gelled gum solutions between ambient and 80xc2x0 C. has not reduced gel strength, indicating that the gels can be thermo-reversible.
The cultured plant cell gums of this invention are useful in a wide variety of applications in part because they are stable over a wide range of temperatures. In an emulsion or solution, the gums are functional over a temperature range of about 0xc2x0 to 100xc2x0 C. at neutral pH. The dried gum powder (neutral pH) is stable over a temperature range of about xe2x88x9270xc2x0 C. to about 10xc2x0 C. If heated, the dried, powdered gum can caramelize. Furthermore, cultured plant cell gums of this invention can provide substantially non-toxic rheological agents (emulsifiers, etc.) of biological origin that can replace potentially harmful synthetic polymers and surface active agents.
The invention also provides isolated (i.e., substantially free of cell biomass) cultured plant cell gums which may be provided as aqueous solutions or suspensions (more or less concentrated than in culture filtrate) or as dried powders. Isolated plant cell gums of this invention include those of plants of the genera: Acacia, Actinidia, Aptenia, Carpobrotus, Chickorium, Cucumis, Glycine, Hibiscus, Hordeum, Letuca, Lycopersicon, Malus, Medicago, Mesembryanthemum, Oryza, Panicum, Phalaris, Phleum, Polianthus, Sida, Solanum, Trifolium, Trigonella, and Zea. Of particular interest are isolated cultured plant cell gums of plants of the family Aizoaceae (including those of the genera Mesembryanthemum, Aptenia, and Carpobrotus).